Fluid hoist



Feb. 21, 1939. P. wl-nfcoms' 2,147,761

- FLUID HOIST- Filed Feb. 29, 1936 5 Sheets-Sheet 1 V IN VENT OR. H26 fan W/u' f'comb ATTORNEYS F" WHITCOMB Feb. 21, 1939.

FLUID HOIS T 5 Sheets-Sheet 2 Filed Feb. 29} 1936 IN VENT OR. P/aifon I'Wu'fconzb Feb. 21, 1939.

P. WHITCOMB FLUID I-IIOIST Filed Feb. 29, 1936 5 Sheets-Sheet 4 ZNVENTOR.

eafon W "fcom b UA/LE OLQ ATTORNEY 5 Sheets-Sheet 5 INVENTOR. sh" whitcomb ATTORNEYS,

P. WH ITCOM B I FLUIDHOIST Filed Feb. 29, 1956 F eb.. 21, 1939.

Patented Feb. 21, 1939 PATENT OFFICE FLUID HOIST Preston Whitcomb, Kenmore, N. Y., assignor to Man g, Maxwell & Moore, Inc., New York,

., a corporation of New Jersey Application February 29, 1936, Serial No. 66,425

This invention is for a hoist oper ted by fluid under pressure. I

An important object of the invention is to providea pressure fluid operated hoist of exceedingly simple and yet compact rugged structure.

Another important object of this invention is to'provide a pressure fluid operated motor hoist in combination with means whereby the speed of rotation of the hoist may be simply and effectively controlled.

A further object of this invention is to provide in a mechanism of this type automatically acting means for changing the speed of rotation of the'hoist as the load thereon varies.

These and other objects are successfully attained by means of the invention herein disclosed.

This invention resides substantially in the clombination, construction, relative location of parts as will be described in detail below.

This application is a continuation in part of my copending application Serial No. 42,571 filed September 28, 1935.

In the drawings,

Figure 1 is an elevational view with some parts Figure 5 is an end elevational view of the mechanism of Figure 1 from the right hand end showing the modification of means for-automatically controlling the speed of operation of the hoist with changes in loads; I

Figure 6 is a cross sectional view on the line 6--6 of Figure 7 showing, a modified form of automatically operated speed control means;

Figure 7 is a cross sectional View taken on the line l-J of Figure 6;

Figure 8 is an end elevational viewfrom the left hand end o f'the engine employing the automatic control means of Figures 6 and '7; and

Figure 9 is a longitudinal cross sectional view through the main shaft showing in diagrammatic perspective form the relative positioning of the gears and passages with respect to the main shaft.

arrangement and 21 Claims. (01. 254-172) This invention involves a hoist comprising a. pressure fluid operated engine having a fixed shaft and an outer rotatable casing in the form .of a cable drum.- The pressure fluid engine portion of the hoist is so constructed that the speed of rotation of the englne'housing, i. e., the cable drum, may be either manually or automatically changed without employing complicated auxiliary mechanism. It is often desirable and in many cases necessary in employing pressure fluid engines to move the cable at a slow speed when under load and at a'hlgh speed when unloaded, i. e., with empty hook.

It is common practice in the commercial use of pressure fluid engines to limit the rate of flow of pressure fluid being pumped to the engine to a range of 6 to 10 feet per second. An engine in accordance with this invention designed to have an output of 25 H. P. and employing a pressure fluid at 500 lbs. per square inch will lift a load of 7500 pounds at 110 feet per minute when supplied with the pressure fluid at the rate of 90 gallons per minute. It is desirable, however, When the hook is empty to take in or pay out the cable at from 600-700 feet per minute. If the cable is moved at 600 feet per minute the engine would require 540 gallons of pressure fluid per minute. The auxiliary equipmentnecessary to meet this wide range of ,gallonage would be expensive and complicated.

The general object of this invention is to provide an engine which may be readily and simply controlled by a manually operated device whereby for the same gallonage per minute of pressure fluid supplied to the engine it may be operated in either direction under load at, for example, 110 feet per minute and with an empty 7 hook at 600-700 feet per minute. An example of this type of service would be on board an airplane c arrier, where the hoist would be employed to raise airplanes from the surface of the ocean to the deck of the carrier. With the motor of this invention the empty hook can be raised or lowered at high speed and raised or lowered at low speed.

In addition to providing the engine with manual I control, this invention may include, where such is desirable, automatic control of the engine speed with changes in load. For example, if an airplane is being raised from the surface of the ocean to deck' level and a wave suddenly raises the airplane, the automatic control under the reduction in load goes into action to speed the engine up, thereby taking up the resulting cable slack. As soon as the cable again goes under I a sealed housing therefor.

tension, the automatic controlreturns the'engine to slow, load-lifting speed.

The mechanism by means of which these oblects are secured will now be described in detafl. The engine is shown comprising a pair of standards and 2,, in which is mounted a hollow shaft 3. This shaft, in the form of device illustrated in Figures 1 to 4 inclusive, is locked in the standards so that it cannot turn. The right hand end of the shaft, as shown in Figure 9, is sealed by means of'a bored tapped plug 3' in which the pressure fluid supply pipe S is secured. The other endof the shaft is closed by means of a cap member 3" and has a threaded bore therein in which is secured the pressure fluid exl jaust Mounted on the shaft between the standards are a number of ball bearing assemblies 4 on which the motor housing which forms the cable drum rotates. This housing comprises a central cylindrical portion 5, the outer surface 6 of which forms the cable drum. The central portion of the hous ing is integral with the hollow heads 1 and 8 which are closed at the ends by means of the cover plates 9 and Hi. The packing gland assemblies II and I2 are provided to prevent fluid leakage at the points where the shaft issues from the ends of the housing. Secured within the head formed by the portions 1 and 9 of the housing is an internal or ring gear I 3 which is secured therein by a series of screws M. In a similar way another internal or ring gear I5 is secured in the portion 8--||l of the housingby means of the machine screws l6. Mounted on each side of the ring gear I3 in the manner shown are the plates I 1 and I8 which fit around the ring gear and form gear I5 is surrounded by the plates l9 and 20. Mounted between the plates l1 and 8 are a series of short shafts 2| which are locked between the plates, as is clear from Figure 1. Referring to Figures 3 and 4, it will be seen that there are six of these shafts mounted between the plates l1 and I8. Journaled on roller bearings on the shafts are the spur gears 22 which mesh with the teeth of the ring gear I3. In the space between these gears is the filler plate 23, the shape of which will be seen from Figure 3. I As will be seen from Figure 3, this filler plate 23 fills in all the space around the spur gears 22 and fits snugly up against the teeth of the ring gear |3 between the spur gears. The spur gears have a close running fit with the circular notches in the filler plate and r thereof between the notches. The construction of the parts in the head 8-||l is the same. Kseries of shafts (not shown) extends between the. plates l9 and 20 and have spur gears 24 thereon which mesh with the ring gear IS. A filler plate 25 is employed in this assembly which has the same shape as the filler plate 23. The plates l1 and I8 and the filler plate 23 are all keyed to the fixed shaft 3 so that they may not rotate thereon (Figure 1). Similarly, the plates l9 and 20 and the filler plate 25 of the other-part of the motor. are likewise keyed to the shaft 3. It will then be noted that when the motor casing revolves on' the bearings 4 to function as a drum it carries Likewise the ring.

ably mounted within the hollow shaft 3.- This control valve comprises a central cylindrical portion 26 having a bore 21 extending from one end towards and terminating near the other end. In other words, the right hand end Figure 9 of bore 21 is closed. As is shown in Figure 9, this bore 21 issues from the left hand end of the sleeve 26. Mounted on one end of the sleeve 25 are a series of flutes 28 around the periphery of the sleeve 26 and spaced from each other as shown. Mounted on the sleeve adjacent the flutes 28, longitudinally spaced therefrom, is another series of flutes 29 which are circumferentially staggered with respect to the flutes 28. Towards the other end of the sleeve 26, but spaced in therefrom a short distance, is another series of flutes 30. Mounted on the extreme end of the sleeve adjacent thereto is a cylindrical piece 3|" which forms a sort of cap for the sleeve but which has a bore so that the passage 21 of the sleeve opens therethrough.

The sets of flutes 28, 29, 38 and cap 3| have an external diameter which is such as to form a tight sliding fit with the interior of the shaft 3. These members form slide bearing members for the sleeve 25 and with it comprise a control valve by means of which the pressure fluid supply to the engine may be controlled. It may be noted that the slide valve assembly may be machined from a solid piece of material or built up or made in any other way apparent to those skilled in the art.

Each of the flutes 28, of which there are six, has

7 a pair of passages 28 and 28 therethrough into the passage 21. All of the passages 28 are circumferentially aligned as are all of the passages 28 Each of the flutes 29 (of which there are six) has a passage 29 therethrough into the passage 21 and all of which are circumferentially aligned. Each of the flutes 30, of which there are six, has a pair of passages 3|! and 30 therethrough into-passage 21. The group of passages 3|] are circumferentially aligned'asare the passages 30". The cap 3| has two diametrically arranged slots 3| which do not open into passage 21 and four holes 3| opening into passage 21. The slots 3| and holes 3| are circumferentially aligned.

Mounted on the end cap 3" of the shaft 3 is a small cylinder 32 in which the piston 33 is mounted. This piston is connected by means of the piston rod 34 to the slide valve as shown in Figure 9. At 35 is a four way control valve. The pipe 35 of this valve is an exhaust pipe and the pipe 39 is a pressure fluid supply pipe. Pipe 31 connects one end of cylinder 32 with'the valve 35 and pipe 38 connects the other end with the valve 35. When the valve is in the position shown in Figure 9, the pressure fluid is supplied from the source through pipe 39, valve 35 and pipe 38 to cylinder 32, exerting apressure on the right hand face of piston 33 so as to move it to the position shown, carrying with it the slide valve assembly within the shaft 3. When the valve 35 is manipulated to its other position, pipe 39 is connected to pipe 31 and pipe 38 is connected to pipe 38, whereby pressure is exerted on the left hand face of piston 33 moving it to the.

extreme right and carrying the slide valve assembly with it.

The plate I1 is provided with six passages extending radially thereof and, uniformly spaced in a circumferential direction around the disc. In a like manner, a similar set of six passages are formed in the plate I8. In making these plates they may be bored inwardly from the outer circumferenceand the outer ends of the bores plugged as indicated in the drawings. Four of the passages in the plate I! and four of the passages 4| in the plate I8 are of the same diameter. Two of the passages 4|) in the plate ill and two of the passages 4| in the plate I8 are of larger diameter than the corresponding passages 4ll and 4|. In the other plates |9 and 29 there are provided in each six equally spaced passages, all of the same smaller diameter, like passages 49, 4| in the plates l1 and i8. Figure 3 shows the relative relationship between these passages. The passages 4|] in the plates H and W are in the same angular position and fall in Figure 3 in line with each other. In other words the passages 40 of the plate |9 lie directly in back of the passages 40 of the plate ill, and similarly the passages 4| of the plate 20 lie directly in back of the passages 4| in the plate M. The passages 4|] and 4| of the plates |9 and 29 corresponding to the large passages it and M are also in alignment, but, being smaller, show up in Figure 3. The relative arrangement of the different sets of passages is illustrated in Figure 9. These passages have been shown diagrammatically in Figure 9 by dash and dot lines to show the relative positioning thereof They, of course, only existas bores in the various plates in accordance with the foregoing description.

As partly indicated in Figure 4, the various plates are mounted upon the shaft 3 so that the passages 40, 4|, 4|] and 4| are in radial alignment-with the short passages in the shaft 3. Several of these short passages have been indicated at 3 in Figure '4. It is likewise to be noted that the short passages are of the same diameter as the longer passages with which they cooperate. This is apparent from Figure 4. Figure 4 also indicates that each of the passages 40 and 40 opens to two of the gears 22 at one side thereof (see also Figure 9). The passages 4| and ll likewise open to these gears on the other side thereof. I The points where these sets of passages open to the same gears are circumferentially spaced, as is clear from the different figures.

When the slide valve is in the position shown in Figure 9, the passages 28 and 39 are in alignment with the passages 3 see Figure 4, in the shaft 9, and of course, with the'six passages ti. The passages in the shaft 9 in alignment with the six passages M in the right hand portion of the engine open into the shaft 9 between the sets of flutes 2t and 29 (see Figure 9). Passages 2t and 29* are blanked ofi until the slide valve is moved to the right, Figure 9. When this occurs passages ii are open to passages 2t and passages l|l are open to passages 29. Thus when piston 9 moves the slide valve to the right all of pas sages it and M of the right hand portion of the engine are connected to passage 21?.

The construction of the left hand portion of the engine is generally similar but differs in some details therefrom. The passagestll, when the slide valve is in the position shown, are in alignment with the passages 9 and the passages in alignment with both. At this time the passages t9 and 49 of the left hand portion of the engine open into shaft 3 through passages 3 formed in the shaft. These passages 3 open into the shaft between the flutes 3|| and the cap which pass therethrough and open into the passage 21 in the sleeve 26. When the slide valve is moved to the right these passages 30 line up with the passages 3 in the shaft 3 whichare in alignment with the passages 4|. Atvthis time all the passages 4| open into passage 21 through the small passages 39*.

Thus with the slide valve to the right all the passages 49, 4| and M open into passage 2| and the two passages 40 open into shaft 3.

. The main fluid pressure pipe S and the main exhaust pipe E may be connected either to the pipes S and E, or to E and S respectively by the four-way valve 3%. a

The operation of this engine will now be described in detail, It is first to be assumed that pressure fluid from any suitable supply source is connected to pipe S, so as to supply the pressure fluid at a pressure of for example 500 pounds per square inch, and at some practical rate of flow per second. It is also to be assumed that ,valve 95 is in the position shown in Figure 9,

so that piston 33 has positioned the slide valve they are open to the space between the flutes 30 and the cap member 3|. Fluid pressure will therefore be supplied to all of the gears to cause them to rotate in the direction of the arrows marked in Figure 9. The fluid will discharge through all of the passages 4| and 4| into the passage 2| since they are all connected thereto. The fluid may then discharge from the left hand end of passage 2| into pipe E and through valve 309 to the main discharge pipe E. Under these conditions the cable drum which is connected to the ring gears it and |5 will revolve in the direction of the arrows applied to the ring gears in Figure 9, and the engine will be operating at slow speed, and for example underan assumed condition to move the cable at 110 feet per minute under a load of 7,500 pounds.

When the cable hook is not loaded the engine may be speeded up to reel the cable at about 600 feet per minute by moving the slide valve to the right. This is accomplished by manipulating valve iii so that the pressure fluid is supplied to the left hand face of piston 99 forcing the slide valve to the right to a position where all of the'passages t9 and 4| open into the passage Z'l leaving only passages til open to the space between the shaft 9 and the slide valve 26. Under these conditions and with valve 3|||l in the position shown in Figure 9, the pressure fluid will only be supplied to the two large passages w and to. the gears associated therewith. The pressure fluid which is discharged from these two gears will enter passage 2]! through the two large discharge passages 4l All of the other passages are open to the passage 27 so that the fluid is free to circulate therethrough under no pressure. Under these conditions the gears will operto revolve at a higher speed.

The previously described low and high speed operation of the cable drum in a reverse direction may be effected by simply operating the main control valve 360 to its other position so'that pipe S is connected to pipe E and pipe E is connected to pipe S. ,With this setting of valve 363 and with the slide valve 26 in the position shown in Figure 9, the engine will operate at slow speed in the reverse direction. Under these circumstances fluid under pressure will -flow from the source through pipe S, valve 360, pipe E into shaft 3 and passage 21. From this passage it will flow to all of the gears through pipes II and ll and be discharged from all of the pipes 46- and 46* to the space between the slide valve and shaft 3. It may then travel through pipe S, valve 366, and pipe E to exhaust or waste. To operate the engine at high speed in this reverse direction slide valve 26 is moved to the right hand position, as previously described, by manipulating valve 35. In this case valve 366 will remain in its last named position so that the pressure fluid is supplied to all of the passages 40, ll and II. The two large passages 40 are open to exhaust, into the space surrounding the slide valve. Under these conditions the engine will operate at high speed in reverse direction and the only fluid that; will be exhausted to pipe .8 will be that discharging through the passages 46'. All of the other passages are connected together with the space 21' so that the fluid will be free to circulate therethrough in a closed circulatory path similar to the action that occurs for the original direction of rotation and high speed operation. In the first case that is with direction of rotation as indicated in Figure 9 the fluid will circulate through the pipes around the passage 21 at no pressure, while in the second instance for high speed operation the fluid will similarly circulate but under pressure.

Several modifications will now bedescrlbed in which the operation of the slide valve is automatlc and under the control of the load of the engine, In the modification shown in Figure 5, the standard 2 is provided with a yoke 52 mounted thereon and supporting a pair of adjustable set screws 53 arranged to limit the oscillatory movement of a lever 56. This lever is mounted upon and attached by means of the key to the shaft 3. In this case the shaft 3 is free to turn in the standards I and 2 but is limited in its turning movement by the set screws 53 coacting with thearm 56. The outer end of the lever 56 is provided with acurved rack 56 which meshes with a gear 51 mounted upon the valve stem of the valve 35. This valve is the same as the valve 35 of the previous engine. Valve 35 is supported upon a bracket 5 and is connected to the cylinder 32 by the pl 31 and 36 as before, and provided with the pressure fluid supply pipe 33 and exhaust pipe 36. The end of arm 56 is connected to the bracket 55 by means of a ate at a much faster rate causing the cable drum the fluid pressure forces which cause rotation of the drum on the shaft. As will be readily apparent, the force which tends to cause clockwise rotation of the drum 6 must react against something and in the particular mechanism disclosed this reaction will be upon the shaft 3 through the gears secured thereto. Rack 56 engaging pinion 51 will move valve 35 to the position shown in Figure 9. If a wave reduces the load on the cable sufliciently by-pushing upward on the airplane or boat, spring 54 will pull arm 50 upwardly, operating valve 35 to the reverse position so that piston 33 will move the slide valve to its other position. The engine will then immediately speed up by reason of the cutting out of the smaller passages, as previously described. The

slide valve 26 does not have any rotative move mentwith respect to shaft 3 during the operations described above but rotates with it as do all the parts mounted upon and connected with the shaft.

As soon as the cable goes under tension again arm 50 will shift downwardly, tensioning spring 54 and resetting valve 35. This will result in a return of the slide valve to the position shown in Figure 9.

The mechanism of Figures 6, 7 and 8 will now be described. In function it is similar to that of Figure 5, but is structurally different. In this arrangement the shaft 3 'is again free to rotate in the standards I and 2 but its rotative movement, however, is confined between close limits "as before by means of the yoke 52, mounted on the standard 2, and thd adjustable stop screws 53, which cooperate with the lever 66 (see Figure 8), which lever is similar to the lever 50 keyed to the shaft 3. A heavy coil spring 58 connects the arm of lever 66 with a'flxed bracket or standard 6|.

The control valve for this mechanism is mounted on the opposite end of shaft 3 and is arranged so that the movable portion of the valve also forms the cylinder for the piston 33 which operates the slide valve. The control valve is mounted upon a bracket 63 supported from the standard I. This bracket .terminates in a ring-shaped casing 66 formed with the chambers 66 and 68 to which the exhaust and supply pipes 6'! and 69 respectively are connected. The movable por-' tion of the valve is shown at 65 in the form of a cylindrical body having a central chamber in which the piston-33 operates. Bolted or otherwise secured to the movable valve member 65 are the side plates 6| which fit on opposite sides of the ring-like terminal 66 of arm 63. Thus the parts 65 and 64 are secured together and attached to the end of shaft 3, as is clear from Figure 7. When shaft 3 oscillates, limited by arm 60, the parts 65 and 64' rotate with it. The manner of forming a tight sliding joint between these parts and the ring member 66 is shown in Figure '7. The movable valve member 65 is provided with four passages l4, l5, l6 and 11, radiating outwardly from the piston cylinder to the periphery. The ring member 66 is provided with four ports, numbered 16 and H, opening into the chamber 66', and I2 and 13, opening into the chamber 66. Referring to Figure 7, the piston 33 is in a position corresponding to that of Figure 9 where the slide valve is positioned to operate the engine at slow speed. In this case lever 66 moves downwardly, engaging the lower stop 53 and tensioning spring 56. This positions valve member 65 to the position shown in Figures 6 and '7 so that pressure fluid may flow from pipe 69 in the chamber 66 through passages 13 and 11 into the cylinder of piston 33 to exert'pr'essure on the right hand face of the piston. This holds the slide valve in a position corresponding to that of Figure 9. When the load is reduced or released on the drum, spring 5t pulls lever to upwardly, carrying shaft 3 with it, and valve member 65 is thus moved to the position where passage "5 communicates with passage I2 and passage l5 communicates with passage, ll. Passages 'M and II are moved out of alignment with the passages i and I3. Fluid then flows from pipe bill and chamber ht through passages I2 and it to the left hand face of piston 33, causing it to move to the right. The pressure fluid in the right hand end of the cylinder is exhausted through passages l5 and ii into chamber t6 and from thence through pipe M. As soon as the load goes on again the valve is repositioned to move piston it to the left, carrying the slide valve with it.

The principle of speed change in fluid engines or pumps as herein described is not limited to use in ageared engine or pump but may equally well be employed in movable vane and piston engines or pumps.

From the above description it will be apparent that the features comprising the novel combination of this invention may be incorporated in other physical forms without departing from the true novelty thereof. I do not, therefore, desire to be strictly limited to the specification and drawings as here presented for purposes, of illustrating the new combination, but rather to the invention as it has been setforth in the following claims.

What I seek to secure by United StatesLetters Patent is:

1. A fluid pressure engine as described, ,comprising a fixed shaft, a casing rotatably mounted on the shaft, a plurality of cooperating gears mounted on the shaft and casing, means forming passages for supplying fluid pressure to and exv hausting it from said gears whereby the casing Will may be rotated on said shaft, and means "for completely closing off some of said supply and exhaust passages whereby the speed of rotation of the casing may be changed.

2. In a fluid pressure engine, a shaft, a casing journal'ed on the shaft, a plurality of intermeshing gear elements respectively connected to said shaft and easing, means forsupplying the fluid under pressure to and exhausting it from said gear elements to eflect relative rotation between the casing and shaft, and means subject to variations in the load on the motor for changing the speed of rotation thereof.

3. In a fluid pressure engine, a shaft, a casing journaled on the shaft, a plurality of intermeshing gear elements respectively connected to said shaft and casing, means for supplying the fluid under pressure to and exhausting it from said gear elements to effect relative rotation between the casing and shaft; and means subject to variations in the load on the motor for cutting out a plurality of the supply and exhaust passages to change the speed of rotation thereof.

t. In a pressure fluid operated engine, the combination comprising a relatively rotatable shaft and easing, a ring gear mounted in said casing, a cage mounted on the shaft, a plurality of spur gears rotatably mounted on said shaft cage and meshing with said ring gear, a supply and exhaust passage for each spur gear, and valve means for cutting out some of said supply and exhaust passages whereby for a constant supply of pressure fluid the speed of rotation of the engine may be varied.

5. In a pressure fluid operated engine, the combination comprising a relatively rotatable shaft and casing, a ring gear mounted in said casing, a cage mounted on said shaft, a plurality of spur gears rotatably mounted on said cage and meshing with said ring gear, a supply and exhaust passage for each spur gear in said cage, and means including a valve subject to variations in load on the engine for cutting in and out of use a plurality of said supply and exhaust passages, whereby the speed of rotation of the engine may be automatically varied.

6. In a pressure fluid operated engine, the combination comprising a fixed shaft, a casing journaled on said shaft, a ring gear secured in said casing, a plurality of spur gears rotatably supported by said shaft and meshing with said ring gear, means forming a supply and exhaust passage for each spur gear, and valve means for cutting in and out of use some of said supply and exhaust passages, whereby the speed of rotation of the casing on theshaft for a constant supply of pressure fluid may be varied.

'7. A pressure fluid operated engine comprising a fixed shaft, a casing mounted for rotation on said shaft, a pair of ring gears mounted in said casing, a plurality of spur gears meshing with each of said ring gears, means for rotatably supporting said spur gears from said shaft,gsaid means having a supply and exhaust passage for each of said spur gears, and valve means for controlling said supply anh exhaust passages whereby a plurality of said spur gears may be cut in or out of circuit to vary the speed of rotation of the casing.

8. A variable speed pressure fluid operated engine including a fixed hollow shaft, a casing rotatably mounted on theshaft, a ring gear secured in said casing, a plurality of spur gears meshing with said ring gear, meansrnounted on said shaft for rotatably supporting the spur gears and formed with a supply and exhaust passage for each spur gear, a valve mounted in said shaft, and means for positioning said valve to cut in or out of circuit a pluralityof'said passages whereby with a constant rate of feed of fluid pressure the speed of the engine may be varied.

9. A variable speed pressure fluid operated engine including a fixed hollow shaft, a casing rotatably mounted on the shaft, a ring gear secured in said casing, a plurality of spur gears meshing with said ring gear, means mounted on said shaft for rotatably supporting the spur gears and formed with a supply and exhaust passage for each spur gear, a valve mounted in said shaft, and pressure fluid operated means for positioning said valve to cut in or out of circuit a plurality of said passages whereby with a constant rate of feed of fluid pressure the speed of the engine may be varied. I

10. A variable speed pressure fluid operated engine including a hollow shaft, a casing rotatably mounted on the shaft, a ring gear secured in said casing, a plurality of spur gears meshing with said ring gear, means mounted on said shaft for rotatably supporting the spur gears, said means forming a supply and exhaust passage for each spur gear, a valve mountedin said shaft, and pressure fluid operated means controlled by and in accordance with variations in the load on the engine for positioning said valve to cut in or out of circuit a plurality of said passpur gears meshing with the ring gear, means for rotatably supporting said spur gears and formed to provide fluid supply and exhaust passages, a valve slidably mounted in said shaft, and fluid pressure operated means for positioning said valve to cut in and out of circuit a plurality of passages.

12. A hoist motor of the type described comprising a fixed hollow shaft, a casing mounted on said shaft for rotation and forming a cable drum, 8. pair of ring gears secured within said casing, .two pairs of spaced supporting plates secured to said shaft, a plurality of spur gears journaled between each of said pairs of plates and meshing with the adjacent ring gears, said plates being formed with supply and exhaust passages, one of each for each spur gear, passages in said shaft in alignment with said supply and exhaust passages, and a slide valve mounted in said shaft and provided with means to control said supply and exhaust passages whereby a plurality of them maybe cut in and out of circuit.

13. A hoist motor of the type described comprising a hollow shaft, a casing mounted on said shaft for rotation and forming a cable drum, a pair of ring gears secured within said casing,

two pairs of spaced supporting plates securedv to said shaft, a plurality of spur gears journaled between each of said pairs of plates and meshing with the adjacent ring gears, said plates being formed with supply and exhaust passages, one of each for each spur gear, passages in said shaft in alignment with said supply and ex haust passages, a slide valve mounted in said shaft and provided with means to control said supply and exhaust passages whereby a plurality of them may be cut in and out of circuit, and means actuated by and in accordance with variation in the load on the engine for shifting said valve.

14. A fluid pressure hoist engine comprising a fixed hollow shaft, a casing journaled for rotation on said shaft and forming a cable drum, a pair of ring gears secured within said casing, inner housings surrounding each of saidring gears and secured to said shaft, a plurality of spur gears journaled in each 61 said inner housings and meshing with the adjacent ring gears, said inner housings being formed with a plurality of pairs of passages comprising a supply and an exhaust passage for each-spur gear, said shaft having passages therethrough in alignment with all of said passages, the supply and exhaust passages for several of said spur gears in one of said inner housings being larger than the others, and a slide valve mounted within said shaft and provided with means to cut in and out of circuit all of said smaller passages while leaving the larger passages always in circuit.

15. A fluid pressure hoist engine comprising a fixed hollow shaft, a casing journaled for rotation on said shaft and forming a cable drum, 9. pair of ring gears secured within said casing, inner housings surrounding each of said ring gears and secured to said shaft, a plurality of spur gears journaled in each of said inner housings and meshing with the adjacent ring gears, said inner housings having a plurality of pairs of passages comprising a supply and an exhaust passage for each spur gear, said shaft having 7 smaller passages while leaving the larger passages always in circuit, and pressure fluid operated means for positioning said valve.

16. A fluid pressure hoist enginev comprising a hollow shaft, a casing journaled for rotation on said shaft and forming a cable drum, a pair of ring gears secured within said casing, inner housings surrounding each of said ring gears and secured to said shaft, a plurality of spur gears journaled in each of said inner housings and meshing with the adjacent ring gears, said inner housings having a plurality of pairs of passages comprising a supply and an exhaust passage for each spur gear, said shaft having passages therethrough in alignment with all of said passages, the supply and exhaust passages for several of said spur gears in one of said ,inner housings being larger than the others, a slide valve mounted within said shaft and positionable to cut in and out of circuit all of said smaller passages while leaving the larger passages always in circuit, and means controlled by and in accordance with variations in load on the engine for positioning said valve.

17. A fluid pressure hoist engine comprising a hollow shaft, acasing journaled for rotation on said shaft and forming a cable drum, a pair of ring gears secured within said casing, inner housings surrounding each of said ring gears and secured to said shaft, a plurality of spur gears journaled in each of said inner housings and meshing with the adjacent ring gears, said inner housings having a plurality of pairs of passages comprising a supply and an exhaust passage for each spur gear, said shaft having passages therethrough in alignment with all of said passages, the supply and exhaust passages for several of said spur gears in one of said inner housings being larger than the others, a slide valve mounted within said shaft and positionable to cut in and out of circuit all of said smaller passages while leaving the larger passages always in circuit, and fluid pressure operated means actuated by and in accordance with variations in the load on the engine for positioning said valve.

18. A pressure fluid operated hoist engine com-. prising a shaft, means for supporting the shaft so that it may oscillate through a small angle, a casing journaled for rotation on said shaft, a ring gear mounted in said casing, a pair of spaced plates supported on said shaft and enclosing said ring gears, a plurality of spur-gears journaled between said plates, said plates having a plurality of pairs of passages, each pair in turn comprising a supply and exhaust passage for each spur gear,

said shaft being hollow and having passages pressure and exhausting it from said elements to effect relative rotation between the casing and shaft including a plurality of passages, and manually operated valve means for sealing off some of the supply and exhaust passages whereby for a constant supply of pressure fluid the speed of rotation of the engine may be varied. p

20. In a fluid pressure engine, a shaft, a casing journaled on the shaft, a plurality of relatively movable elements respectively connected to the shaft and easing, means for supplying fluid under pressure to and exhausting it from said elements to effect relative rotation between the casing and shaft including a plurality of passages, and automatically operated valve means for cutting out some of said supply and exhaust passages whereby.

for a constant supply of pressure fluid the-speed of rotation of the engine may be varied.

21. In a fluid pressure engine, a shaft, a casing mounted on the shaft whereby relative rotation therebetween may occur, a plurality of relatively movable elements respectively connected to the shaft and easing, means for supplying fluid under pressure to and exhausting it from said elements to effect relative rotation between the casing and shaft, and means operated by and in accordance with variations in the load on the engine for cutting in and out of use a plurality of said supply and exhaust passages whereby the speed of rotation of the engine may be automatically varied.

- PRESTON WHITCOMB. 

